It's a bit too much to take in in one reading, Kevin, but my immediate reaction is for you to consult Bronson. Secondly, the tunes used for ballad texts are often much younger than the ballads themselves. It's always worth remembering that there is no definite tune family anywhere; all that can be said is that there are related tunes and cadences that usually end up with a chicken-and-egg debate and, in my experience, have a secular or art music origin. Then again, the area of the super-variant cannot be discounted. A good example is the 'Dark-eyed sailor', the tune crops up again and again with in the tradition, much the same as the 'Vilikins' melody. Certain cadences from either tune introduce a variant that comes close to repcomposition, my point being that maybe this is what you are experiencing with the airs in your above post. Captain Wedderburn's Courtship is another good example of tune sharing, but then again, authorship has been claimed by Besom Jimmy, a Scots Traveller. I collected the tune from one of the Blackpool Gypsy Folk attached to the John Reilly song.
To sum up, it is not unusual to find a tune sharing family in all areas of the British Tradition. As I suggested, Bronson may give you some idea of the tune's structure and origin, and the earliest version which my be worth pursuing.